Adapter and method for charging control

1. An adapter, comprising: a power converting unit, configured to convert an input alternating current (AC) to obtain an output voltage and an output current of the adapter, wherein the output current of the adapter is a current of a first pulsating waveform; a sample and hold unit, connected to the power converting unit, and configured to sample the current of the first pulsating waveform when the sample and hold unit is in a sample state and hold a peak value of the current of the first pulsating waveform when the sample and hold unit is in a hold state; and a current acquisition and control unit, connected to the sample and hold unit, and configured to determine whether the sample and hold unit is in the hold state and acquire the peak value of the current of the first pulsating waveform held by the sample and hold unit when the sample and hold unit is in the hold state.

2. The adapter of claim 1 , further comprising: a voltage adjusting unit, connected to the power converting unit and configured to detect and adjust the output voltage of the adapter, wherein the current acquisition and control unit is connected to the voltage adjusting unit and configured to adjust the peak value of the current of the first pulsating waveform via the voltage adjusting unit.

3. The adapter of claim 2 , wherein the voltage adjusting unit comprises: a voltage dividing unit, having an input end connected to the power converting unit, and configured to divide the output voltage of the adapter by a voltage division ratio to generate a second voltage; a voltage comparing unit, having an input end connected to an output end of the voltage dividing unit, and configured to compare the second voltage with a second reference voltage; and a voltage control unit, having an input end connected to the input end of the voltage comparing unit and an output end connected to the power converting unit, and configured to control the output voltage of the adapter based on a comparison result between the second voltage and the second reference voltage, the current acquisition and control unit being connected to the voltage comparing unit and configured to adjust the peak value of the current of the first pulsating waveform through adjusting the voltage division ratio.

4. The adapter of claim 3 , wherein the current acquisition and control unit comprises a control unit, and the voltage dividing unit comprises a digital potentiometer; the digital potentiometer having a high-potential end connected to the power converting unit, a low-potential end grounded, and an output end connected to the voltage comparing unit; the control unit is connected to a control end of the digital potentiometer and configured to adjust the voltage division ratio of the digital potentiometer via the control end of the digital potentiometer, so as to adjust the peak value of the current of the first pulsating waveform.

5. The adapter of claim 1 , wherein the current acquisition and control unit is configured to receive a sync signal and determine based on the sync signal whether the sample and hold unit is in the hold state, wherein the period of the sync signal is 1/N of the period of the first pulsating waveform, and wherein N is an integer greater than or equal to one.

6. The adapter of claim 5 , wherein the current acquisition and control unit is configured to determine based on the sync signal whether the first pulsating waveform is on the peak or falling edge and acquire the peak value of the current of the first pulsating waveform held by the sample and hold unit when the first pulsating waveform is on the peak or falling edge.

7. The adapter of claim 6 , wherein the current acquisition and control unit comprises: a comparator and a control unit, wherein the comparator has a first input end configured to receive the sync signal and a second input end configured to receive a reference voltage, the control unit is connected to an output end of the comparator and configured to determine based on a comparison result between the voltage of the sync signal and the reference voltage whether the first pulsating waveform is on the peak or falling edge.

8. The adapter of claim 1 , wherein the current acquisition and control unit is further configured to control the sample and hold unit to switch from the hold state to the sample state after the current acquisition and control unit acquires the peak value of the current of the first pulsating waveform.

9. The adapter of claim 8 , wherein the sample and hold unit comprises a capacitor and is configured to hold the peak value of the current of the first pulsating waveform based on the capacitor of the sample and hold unit, and wherein the current acquisition and control unit comprises a discharging unit and a control unit, the discharging unit is connected to the control unit and the capacitor of the sample and hold unit respectively and configured to release the charge across the capacitor of the sample and hold unit under the control of the control unit, whereby the sample and hold unit switches from the hold state to the sample state.

10. The adapter of claim 1 , wherein the sample and hold unit comprises: a current sampling unit, connected to the power converting unit, and configured to detect the current of the first pulsating waveform to obtain a sampling current and convert the sampling current to a sampling voltage, wherein the sampling voltage is configured to indicate the magnitude of the current of the first pulsating waveform; and a current holding unit, connected to the current sampling unit and the current acquisition and control unit, and configured to receive the sampling voltage from the current sampling unit and charge the capacitor of the current holding unit based on the sampling voltage, wherein the current acquisition and control unit is configured to acquire the peak value of the current of the first pulsating waveform by detecting a voltage across the capacitor of the sample and hold unit.

11. The adapter of claim 1 , the adapter being operable in a first charging mode and a second charging mode, wherein charging speed of a device to be charged by the adapter in the second charging mode is faster than the charging speed of the device to be charged by the adapter in the first charging mode, wherein the current of the first pulsating waveform is the output current of the adapter in the second charging mode, and wherein the adapter comprises a control unit, which is configured to perform two-way communication with the device to be charged to control the output of the adapter in the second charging mode, when the adapter is connected to the device to be charged.

12. The adapter of claim 11 , wherein the control unit configured to perform two-way communication with the device to be charged to control the output of the adapter in the second charging mode is configured to: perform two-way communication with the device to be charged to negotiate a charging mode between the adapter and the device to be charged.

13. The adapter of claim 11 , wherein the control unit configured to perform two-way communication with the device to be charged to control the output of the adapter in the second charging mode is configured to: perform two-way communication with the device to be charged, to determine a charging voltage, which is output from the adapter in the second charging mode for charging the device to be charged; and the control unit is configured to adjust the output voltage of the adapter, whereby the output voltage of the adapter is equal to the charging voltage that is output from the adapter in the second charging mode for charging the device to be charged.

14. The adapter of claim 11 , wherein the control unit configured to perform two-way communication with the device to be charged to control the output of the adapter in the second charging mode is configured to: perform two-way communication with the device to be charged to determine a charging current, which is output from the adapter in the second charging mode for charging the device to be charged; and adjust the peak value of the current of the first pulsating waveform, whereby the peak value of the current of the first pulsating waveform is equal to the charging current that is output from the adapter in the second charging mode for charging the device to be charged.

15. The adapter of claim 11 , wherein the control unit configured to perform two-way communication with the device to be charged to control the output of the adapter in the second charging mode is configured to: perform two-way communication with the device to be charged to adjust the peak value of the current of the first pulsating waveform, in the process of charging with the second charging mode.

16. The adapter of claim 1 , wherein the adapter is operable in a first charging mode and a second charging mode, the first charging mode is a constant-voltage mode and the second charging mode is a constant-current mode; the current of the first pulsating waveform is the output current of the adapter in the second charging mode; wherein the adapter comprises a control unit, the power converting unit comprises a secondary filter unit, and the control unit is connected to the secondary filter unit, wherein in the first charging mode, the control unit is configured to control the secondary filter unit to operate to make the voltage value of the output voltage of the adapter stable, and in the second charging mode, the control unit is configured to control the secondary filter unit to stop operating such that the current output from the adapter becomes the current of the first pulsating waveform.

17. A method for charging control for an adapter, the method comprising: determining whether a sample and hold unit is in a hold state, wherein the adapter comprises a power converting unit and the sample and hold unit, the power converting unit is configured to convert an input alternating current (AC) to obtain an output voltage and an output current of the adapter, and the output current of the adapter is a current of a first pulsating waveform; wherein the sample and hold unit is connected to the power converting unit and configured to sample the current of the first pulsating waveform when the sample and hold unit is in a sample state and hold a peak value of the current of the first pulsating waveform when the sample and hold unit is in the hold state; and acquiring the peak value of the current of the first pulsating waveform held by the sample and hold unit when the sample and hold unit is in the hold state.

18. The method of claim 17 , wherein the adapter further comprises a voltage adjusting unit, which is connected to the power converting unit and configured to detect and adjust the output voltage of the adapter, and wherein the method further comprises: adjusting the peak value of the current of the first pulsating waveform through the voltage adjusting unit.

19. The method of claim 18 , wherein the voltage adjusting unit comprises: a voltage dividing unit, having an input end connected to the power converting unit, and configured to divide the output voltage of the adapter by a voltage division ration to generate a second voltage; a voltage comparing unit, having an input end connected to an output end of the voltage dividing unit, and configured to compare the second voltage with a second reference voltage; and a voltage control unit, having an input end connected to the input end of the voltage comparing unit and an output end connected to the power converting unit, and configured to control the output voltage of the adapter based on a comparison result between the second voltage and the second reference voltage, wherein adjusting the peak value of the current of the first pulsating waveform through the voltage adjusting unit comprises: adjusting the peak value of the current of the first pulsating waveform through adjusting the voltage division ration.

20. The method of claim 19 , wherein the voltage dividing unit comprises a digital potentiometer, which has a high-potential end connected to the power converting unit, a low-potential end grounded, and an output end connected to the voltage comparing unit, and wherein adjusting the peak value of the current of the first pulsating waveform through adjusting the voltage division ration comprises: adjusting the voltage division ration of the digital potentiometer to adjust the peak value of the current of the first pulsating waveform.

21. The method of claim 17 , wherein determining whether the sample and hold unit is in the hold state comprises: receiving a sync signal, wherein the period of the sync signal is 1/N of the period of the first pulsating waveform, and wherein N is an integer greater than or equal to one; and determining based on the sync signal whether the sample and hold unit is in the hold state.

22. The method of claim 17 , wherein the adapter is operable in a first charging mode and a second charging mode, and charging speed of a device to be charged by the adapter in the second charging mode is faster than the charging speed of the device to be charged by the adapter in the first charging mode, wherein the current of the first pulsating waveform is the output current of the adapter in the second charging mode, and the method further comprises: performing two-way communication with the device to be charged to control the output of the adapter in the second charging mode, when the adapter is connected to the device to be charged.

23. The method of claim 17 , wherein the adapter is operable in a first charging mode and a second charging mode, the first charging mode is a constant-voltage mode and the second charging mode is a constant-current mode, the current of the first pulsating waveform is the output current of the adapter in the second charging mode; wherein the adapter comprises a control unit, the power converting unit comprises a secondary filter unit, and the control unit is connected to the secondary filter unit, and wherein the method further comprises: controlling, in the first charging mode, the secondary filter unit to operate such that the voltage value of the output voltage of the adapter keeps constant; and controlling, in the second charging mode, the secondary filter unit to stop operating such that the output current of the adapter becomes the current of the first pulsating waveform.